Acratocnus is an extinct genus of Caribbean sloths that were found on Cuba, Hispaniola (today the Dominican Republic and Haiti), and Puerto Rico during the Late Pleistocene and early-mid Holocene.
| Acratocnus | |
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| Acratocnus ye skull | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Pilosa |
| Family: | †Megalocnidae |
| Genus: | †Acratocnus Anthony 1916 |
| Type species | |
| †Acratocnus odontrigonus Anthony, 1916
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| Species | |
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| Synonyms | |
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Taxonomy
editThe genus was first described by American paleontologist Harold Elmer Anthony in 1916 based on the species A. odontrigonus, which was found in cave deposits in Puerto Rico.[1] Acratocnus antillensis was first described by William Diller Matthew in 1931. The species was identified based on fossil remains found in various locations in Cuba, including the paleontological deposit Las Llanadas, Sancti Spíritus Province.[2][3] Acratocnus ye was first described by Ross D. E. MacPhee, Jennifer L. White, and Charles A. Woods in 2000. The species was identified based on fossil remains found in various locations in Haiti, including the type locality at Trouing Vape`Deron, Plain Formon, Département du Sud.[4] The holotype specimen, UF170533, consists of a skull and mandible.[5] Acratocnus simorhynchus was first described in 2002. The species was identified based on fossil remains found in Cueva del Perezoso, located in Jaragua National Park, Pedernales Province, Dominican Republic.[6] The holotype, catalogued as ALF 7194, includes an unusually well-preserved skull, mandible, and post-cranial elements.[6]
Like all of the Antillean sloths, Acratocnus was formerly thought on the basis of morphological evidence to be a member of the family Megalonychidae, which was also thought to include Choloepus, the two-toed tree sloths. Recent molecular evidence has clarified that Caribbean sloths represent a separate basal branch of the sloth radiation,[7][8] now placed in the family Megalocnidae.[7]
Description
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Acratocnus ye and A. odontrigonus have been estimated to weigh approximately 15 kilograms (33 lb), while A. antillensis is estimated to be somewhat smaller at around 10 kilograms (22 lb).[9] All species of Acratocnus were somewhat larger than living tree sloths, though small in comparison to mainland ground sloths.[5] The skulls of Acratocnus are markedly domed along their sagittal crests.[4] The skull of A. antillensis is distinguished from other species within the genus Acratocnus by its prominent palatine foramina and a short, pointed symphyseal spout.[10][11] The skull of A. simorhynchus is distinguished by its prominent frontal sinuses, resulting in a foreshortened snout. The species also exhibits a pronounced medio-lateral flare of the rostrum, a short symphyseal spout, and deep mandibular corpus.[12][13] The skull of A. ye is distinguished by its flattened nose, giving it a "snub nosed" look.[5]
Ecology
editSpecies of Acratocnus inhabited forested environments. The various species are though to have been semi-arboreal, having spent some of their time in trees and some on the ground,[5] with their hooked claws being used both for climbing and terrestrial foraging.[12]
Extinction
editThe various species of Caribbean sloths are thought to have become extinct following human arrival to the Caribbean during the mid-Holocene around 6,000 years ago based on the timing of the last radiocarbon dates of Caribbean sloths.[14] Several radiocarbon dates of A. antiliensis on Cuba support the presence of the species on the island up until human arrival. Remains of Caribbean sloths have been found in a number of archaeological sites suggesting that they may have been consumed by the earliest inhabitants of the Caribbean, although evidence of hunting is inconclusive.[15]
See also
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References
edit- ^ Anthony, H. E. 1918. The indigenous land mammals of Porto Rico, living and extinct. Mem. Am. Mus. Nat. Hist. n. ser. 2: 331–435.
- ^ Rodriguez-Silva, Ricardo (2021). "Biogeography of the West Indies: A complex scenario for species radiations". Ecology and Evolution. 11 (14): 9447–9463. doi:10.1002/ece3.7771. PMC 8293766. PMID 34306640.
- ^ Orihuela, Johanset; Suarez, William; Balseiro, Diego (2020). "Late Holocene land vertebrate fauna from Cueva de los Nesofontes: Stratigraphy, chronology and paleoecology". Historical Biology. 32 (5): 596–607. doi:10.1080/08912963.2019.1618294.
- ^ a b MacPhee, R. D. E.; White, Jennifer L.; Woods, Charles A. (2000). "New Megalonychid Sloths (Phyllophaga, Xenarthra) from the Quaternary of Hispaniola". American Museum Novitates (3303): 1–32.
- ^ a b c d Gaudin, Timothy J.; Scaife, Thomas (22 August 2022). "Cranial osteology of a juvenile specimen of Acratocnus ye (Mammalia, Xenarthra, Folivora) and its ontogenetic and phylogenetic implications". The Anatomical Record. 306 (3): 607–637. doi:10.1002/ar.25062. ISSN 1932-8486. PMID 36054593.
- ^ a b Rega, Elizabeth; McFarlane, Donald A.; Lundberg, Joyce; Christenson, Keith (2002). "A new megalonychid sloth from the late Wisconsinan of the Dominican Republic". Caribbean Journal of Science. 38 (1–2): 11–19.
- ^ a b Presslee, S.; Slater, G. J.; Pujos, F.; Forasiepi, A. M.; Fischer, R.; Molloy, K.; Mackie, M.; Olsen, J. V.; Kramarz, A.; Taglioretti, M.; Scaglia, F.; Lezcano, M.; Lanata, J. L.; Southon, J.; Feranec, R.; Bloch, J.; Hajduk, A.; Martin, F. M.; Gismondi, R. S.; Reguero, M.; de Muizon, C.; Greenwood, A.; Chait, B. T.; Penkman, K.; Collins, M.; MacPhee, R.D.E. (2019). "Palaeoproteomics resolves sloth relationships" (PDF). Nature Ecology & Evolution. 3 (7): 1121–1130. Bibcode:2019NatEE...3.1121P. doi:10.1038/s41559-019-0909-z. PMID 31171860. S2CID 174813630.
- ^ Delsuc, F.; Kuch, M.; Gibb, G. C.; Karpinski, E.; Hackenberger, D.; Szpak, P.; Martínez, J. G.; Mead, J. I.; McDonald, H. G.; MacPhee, R.D.E.; Billet, G.; Hautier, L.; Poinar, H. N. (2019). "Ancient Mitogenomes Reveal the Evolutionary History and Biogeography of Sloths". Current Biology. 29 (12): 2031–2042.e6. Bibcode:2019CBio...29E2031D. doi:10.1016/j.cub.2019.05.043. hdl:11336/136908. PMID 31178321.
- ^ McDonald, H. Gregory (June 2023). "A Tale of Two Continents (and a Few Islands): Ecology and Distribution of Late Pleistocene Sloths". Land. 12 (6): 1192. doi:10.3390/land12061192. ISSN 2073-445X.
- ^ White, Jennifer L.; MacPhee, Ross (2001). "The Sloths of the West Indies: A Systematic and Phylogenetic Review". In Woods, Charles A.; Sergile, Florence E. (eds.). Biogeography of the West Indies: Patterns and Perspectives. CRC Press. ISBN 9780429124549.
- ^ McAfee, Robert K.; Beery, Sophia M. (2019). "Intraspecific variation of Megalonychid sloths from Hispaniola and the taxonomic implications". Historical Biology. 33 (3): 371–386. doi:10.1080/08912963.2019.1618294.
- ^ a b Rega, Elizabeth; McFarlane, Donald A.; Lundberg, Joyce; Christenson, Keith (2002). "A new megalonychid sloth from the late Wisconsinan of the Dominican Republic". Caribbean Journal of Science. 38 (1–2): 11–19.
- ^ Gaudin, Timothy (2004). "Phylogenetic relationships among sloths (Mammalia, Xenarthra, Tardigrada): the craniodental evidence". Zoological Journal of the Linnean Society. 140 (2): 255–305. doi:10.1111/j.1096-3642.2003.00100.x.
- ^ Steadman, David W.; Martin, Paul S.; MacPhee, Ross D. E.; Jull, A. J. T.; McDonald, H. Gregory; Woods, Charles A.; Iturralde-Vinent, Manuel; Hodgins, Gregory W. L. (2005-08-16). "Asynchronous extinction of late Quaternary sloths on continents and islands". Proceedings of the National Academy of Sciences. 102 (33): 11763–11768. Bibcode:2005PNAS..10211763S. doi:10.1073/pnas.0502777102. ISSN 0027-8424. PMC 1187974. PMID 16085711.
- ^ Orihuela, Johanset; Viñola, Lázaro W.; Jiménez Vázquez, Osvaldo; Mychajliw, Alexis M.; Hernández de Lara, Odlanyer; Lorenzo, Logel; Soto-Centeno, J. Angel (December 2020). "Assessing the role of humans in Greater Antillean land vertebrate extinctions: New insights from Cuba". Quaternary Science Reviews. 249: 106597. Bibcode:2020QSRv..24906597O. doi:10.1016/j.quascirev.2020.106597.